1. Field of the Invention
The present invention relates generally to lens shift mechanisms and in particular to a lens shift mechanism preferably applied to a projector for digital cinema.
2. Description of the Related Art
A projector (see e.g. Japanese Patent Laid-Open No. Hei 5-040308) is provided with a lens shift mechanism which vertically moves a lens in order to adjust vertical positions of images on a screen.
The lens shift mechanism is such that a member attached with the lens (hereinafter called the lens attachment member) is mounted to a fixing member so as to be vertically movable, whereby the lens is vertically moveable. Such a vertically movable mount method has adopted a method in which a guide member is used such as an arimizo type guide, a linear guide, a ball bushing or the like and a spacer is used to adjust the anteroposterior positions of the lens. In addition, a drive method using a screw and a nut has been adopted as the method of vertically driving the lens.